This invention relates to a holding device for vertically positioning a window pane, which can be bonded the frame of a motor vehicle.
Stick-on window panes, such as for example windshields, are usually inserted automatically with a free arm robot. In this case, the panes must be located at a constant distance from the window frame and positioned by means of holding devices until the adhesive sets. For vehicle body construction, holding devices with automatic adjustment of the support elements to the respective height of the lower edge of the window pane have been used to an increasing degree in addition to holding devices with manually adjustable support faces.
This invention is based on a holding device of the type disclosed in published European Patent Application No. 0 230 837 B1. In this device, support bars are arranged at small intervals one above the other and are integrally connected to a holding part by means of elastically compressible spring legs. After the window pane has been placed in the desired position, its lower edge rests on the support bar located immediately below it, whereas the support bars located above the edge are pressed in to an out-of-the-way position by the window pane.
However, when the window pane is placed in position by a robot arm, deviations in tolerance with respect to the window frame frequently result which have to be compensated for by a readjustment of the window pane after it has already been pressed onto the adhesive material. This requires a subsequent displacement of the window pane in the installation plane, in which case the upper edge of the window pane has to be aligned with the upper transverse frame to a specific prescribed degree.
In the known holding device, a downward compensation movement is possible by manually pressing in the bars which are supporting the pane. On the other hand, if an upward compensation movement of the window pane is required, the last support bar that has been pressed in by the edge of the window pane will spring back as the pane is raised due to the restoring force of its spring legs, and thus support the window pane at a new level.
However, this holding device has various disadvantages which have prevented motor vehicle manufacturers from generally using them for the temporary positioning of windshields. First, the thickness of the support bars, which is required for structural reasons, results in an excessively large gradation between the individual support faces. Secondly, a specific spacing exists between the individual support bars for technical reasons associated with their removal from molds, which spacing will allow compression of the bars by the window pane being supported before the supporting effect of the holding device can be achieved. The higher the position at which the lower edge of the window pane is to be placed, the more support bars that have to be compressed onto one another and thus the further the window pane will slip downwards until all the bars are lying securely on top of one another. Thus, the positioning is too inaccurate for practical application. Finally, this holding device cannot be injection molded in a simple two-part casting mold, but instead requires a separate mold-removal slide in order to be able to remove from the mold the intermediate space between the laterally bent spring legs, which necessarily raises manufacturing costs.
In view of the requirements placed on the holding device and in view of the fact that its support function is only required temporarily until the bonding process is completed, an object of the present invention is to design the holding device in such a way that a finer gradation is achieved between the individual support faces and the support faces are largely prevented from giving way when loaded by the window pane. In addition, the manufacturing costs are to be kept as low as possible.